Encoding method and encoding apparatus

ABSTRACT

A filtering method according to the present invention is for filtering a plurality of blocks included in an image, and comprises: determining whether each of the blocks is an IPCM block or not; filtering a non-IPCM block that is not an IPCM block among the blocks to generate filtered data; outputting the filtered data as pixel values of the non-IPCM block, and outputting pixel values of the unfiltered IPCM block as pixel values of the IPCM block.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional PatentApplication No. 61/445,115 filed on Feb. 22, 2011. The entire disclosureof the above-identified application, including the specification,drawings and claims is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a filtering method, a moving picturecoding apparatus, a moving picture decoding apparatus, and a movingpicture coding and decoding apparatus.

BACKGROUND ART

Intra Pulse Code Modulation (IPCM) blocks are blocks of uncompressedvideo or image samples where luma and chroma samples are coded in thecoded stream. These blocks are used in the case when the entropy codingunit produces more bits rather than reduces bits when coding the blocksof image samples.

In other words, the pixel values of the IPCM blocks are not compressed,ant thus the raw pixel values of the original image are used. The IPCMblock is introduced in the H.264/AVC Video Compression Standard.

When IPCM blocks are coded in a coded stream in the H.264 VideoCompression Standard, these IPCM blocks are coded as uncompressed data.No decoding is performed for these blocks. However, post-decodingprocessing (including filtering such as deblocking filtering) is stillperformed on the block boundaries which tend to be a cause ofdeterioration in image quality (for example, see Non-patent Literature(NPL) 1).

CITATION LIST Non Patent Literature

[NPL 1]

-   ISO/IEC 14496-10 “MPEG-4 Part 10 Advanced Video Coding”

SUMMARY OF INVENTION Technical Problem

However, in the aforementioned conventional art, filtering is performedalso on the boundary of both kinds of blocks that are an IPCM block anda non-IPCM block. Here, an IPCM block is a block as to which theoriginal pixel values are used. Thus, the conventional art has a problemthat the image quality of IPCM blocks deteriorates when filtering isperformed.

The present invention aims to provide a filtering method which enablessuppression of deterioration in the image quality of IPCM blocks.

Solution to Problem

In order to achieve the aforementioned object, a filtering methodaccording to an aspect of the present invention is for filtering aplurality of blocks included in an image, the filtering methodcomprising: determining whether or not each of the blocks is an IntraPulse Code Modulation (IPCM) block; filtering a non-IPCM block which isnot the IPCM block out of the blocks to generate filtered data; andoutputting the filtered data as a value of a pixel in the non-IPCMblock, and outputting, as a value of a pixel in the IPCM block, anunfiltered value of the pixel in the IPCM block.

With this structure, the filtering method according to an embodiment ofthe present invention does not involve filtering on an IPCM block, andthus is capable of suppressing degradation in image quality of the IPCMblock.

In addition, in the filtering, the filtered data of the non-IPCM blockmay be generated by performing filtering using both the value of thepixel in the IPCM block and the value of the pixel in the non-IPCMblock.

In addition, the filtering may be deblocking filtering, in thefiltering, first filtered data may be generated by filtering a firstnon-IPCM block out of a first IPCM block and the first non-IPCM blockwhich are adjacent to each other, and in the outputting, the firstfiltered data may be output as a value of a pixel in the first non-IPCMblock, and an unfiltered value of a pixel in the first IPCM block may beoutput as a value of the pixel in the first IPCM block.

In addition, in the filtering, only the non-IPCM block out of the blocksmay be filtered, and the IPCM block does not need to be filtered.

In addition, in the filtering, the filtered data may be generated byfiltering all of the blocks, and in the outputting, a filtered value ofthe pixel in the IPCM block in the filtered data may be replaced by theunfiltered value of the pixel in the IPCM block.

Furthermore, a filtering method according to an aspect of the presentinvention is for filtering a boundary between an Intra Pulse CodeModulation (IPCM) block and a non-IPCM block which are adjacent to eachother in an image, the filtering method comprising: setting a firstfilter strength for the non-IPCM block, and setting a second filterstrength for the IPCM block, the second filter strength being lower thanthe first filter strength; and filtering the non-IPCM block using thefirst filter strength, and filtering the IPCM block using the secondfilter strength.

With this structure, the filtering method according to an embodiment ofthe present invention is capable of reducing the strength of filteringon the IPCM block, and thereby suppressing degradation in image qualityof the IPCM block.

In addition, the second filter strength may specify that filtering isskipped.

With this structure, the filtering method according to an embodiment ofthe present invention does not involve filtering on an IPCM block, andthus is capable of suppressing degradation in image quality of the IPCMblock.

In addition, the first filter strength may be lower than a filterstrength that is determined when the non-IPCM block is a block to beintra coded.

It is to be noted that the present invention can be realized as not onlysuch a filtering method but also as a filtering apparatus includingunits corresponding to the unique steps included in the filteringmethod, and as a program for causing a computer to execute these uniquesteps. Naturally, such a program can be distributed throughnon-transitory computer-readable recording media such as CD-ROM etc. andcommunication media such as the Internet.

Furthermore, the present invention can be realized as a moving picturecoding method and a moving picture decoding method each including such afiltering method. Furthermore, the present invention can be implementedas a moving picture coding apparatus and a moving picture decodingapparatus each including a filtering device, and as a moving picturecoding and decoding apparatus including the moving picture codingapparatus and the moving picture decoding apparatus. Furthermore, thepresent invention can be implemented as a semiconductor integratedcircuit (LSI) which exerts part or all of the functions of the filteringdevice, the moving picture coding apparatus, or the moving picturedecoding apparatus.

Advantageous Effects of Invention

The present invention provides a filtering method which enablessuppression of deterioration in the image quality of IPCM blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present invention. In the Drawings:

FIG. 1 is an illustration of a method of determining a filter strengthat a block boundary between an IPCM block and a non-IPCM block, in theH.264 Standard;

FIG. 2 is a flowchart of processes of filtering at a block boundary, inthe H.264 Standard;

FIG. 3 is a flowchart of processes of determining a filter strength, inthe H.264 Standard;

FIG. 4 is an illustration of a filter strength in a filtering methodaccording to Embodiment 1 of the present invention;

FIG. 5 is a flowchart of a filtering method according to Embodiment 1 ofthe present invention;

FIG. 6 is a block diagram of a moving picture coding apparatus accordingto Embodiment 1 of the present invention;

FIG. 7A is an illustration of an example of a block boundary accordingto Embodiment 1 of the present invention;

FIG. 7B is an illustration of an example of a block boundary accordingto Embodiment 1 of the present invention;

FIG. 8A is an illustration of operations performed by a filtering unitaccording to Embodiment 1 of the present invention;

FIG. 8B is an illustration of operations performed by a filtering unitaccording to Embodiment 1 of the present invention;

FIG. 9 is a block diagram of an image decoding apparatus according toEmbodiment 1 of the present invention;

FIG. 10A is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1 of the present invention;

FIG. 10B is an illustration of an exemplary structure of a filteringunit according to Embodiment 1 of the present invention;

FIG. 10C is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1 of the present invention;

FIG. 10D is an illustration of an exemplary structure of a filteringunit according to Embodiment 1 of the present invention;

FIG. 10E is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1 of the present invention;

FIG. 10F is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1 of the present invention;

FIG. 10G is an illustration of an exemplary structure of filtering unitsaccording to Embodiment 1 of the present invention;

FIG. 10H is an illustration of an exemplary structure of a filteringunit according to Embodiment 1 of the present invention;

FIG. 11 is a flowchart of a filtering method according to Embodiment 1of the present invention;

FIG. 12 is a flowchart of a filtering method according to Embodiment 1of the present invention;

FIG. 13 is an illustration of filter strengths and block units accordingto Embodiment 1 of the present invention;

FIG. 14A is an illustration of an application range of a flag indicatingthat a filter is ON according to a comparison example in the presentinvention;

FIG. 14B is an illustration of an application range of a flag indicatingthat a filter is ON according to Embodiment 1 of the present invention;

FIG. 15 shows an overall configuration of a content providing system forimplementing content distribution services;

FIG. 16 shows an overall configuration of a digital broadcasting system.

FIG. 17 shows a block diagram illustrating an example of a configurationof a television;

FIG. 18 shows a block diagram illustrating an example of a configurationof an information reproducing/recording unit that reads and writesinformation from and on a recording medium that is an optical disk;

FIG. 19 shows an example of a configuration of a recording medium thatis an optical disk;

FIG. 20A shows an example of a cellular phone;

FIG. 20B is a block diagram showing an example of a configuration of acellular phone;

FIG. 21 illustrates a structure of multiplexed data;

FIG. 22 schematically shows how each stream is multiplexed inmultiplexed data;

FIG. 23 shows how a video stream is stored in a stream of PES packets inmore detail;

FIG. 24 shows a structure of TS packets and source packets in themultiplexed data;

FIG. 25 shows a data structure of a PMT;

FIG. 26 shows an internal structure of multiplexed data information;

FIG. 27 shows an internal structure of stream attribute information;

FIG. 28 shows steps for identifying video data;

FIG. 29 shows an example of a configuration of an integrated circuit forimplementing the moving picture coding method and the moving picturedecoding method according to each of embodiments;

FIG. 30 shows a configuration for switching between driving frequencies;

FIG. 31 shows steps for identifying video data and switching betweendriving frequencies;

FIG. 32 shows an example of a look-up table in which video datastandards are associated with driving frequencies;

FIG. 33A is a diagram showing an example of a configuration for sharinga module of a signal processing unit; and

FIG. 33B is a diagram showing another example of a configuration forsharing a module of the signal processing unit.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention are described indetail with reference to the Drawings. Each of the embodiments describedbelow shows a preferred specific example of the present invention. Thenumerical values, shapes, materials, structural elements, thearrangement and connection of the structural elements, steps, theprocessing order of the steps etc. shown in the following embodimentsare mere examples, and therefore do not limit the present invention. Thepresent invention is defined by the Claims. Therefore, among thestructural elements in the following embodiments, the structuralelements not recited in any one of the independent Claims defining themost generic concept of the present invention are not necessarilyrequired to achieve the aim of the present invention. Such optionalstructural elements are described as structural elements ofcorresponding ones of preferred embodiments.

Before giving descriptions of the embodiments of the present invention,a description is given of inter-pixel filtering (deblocking filtering)in a boundary between an IPCM block and a non-IPCM block in coding anddecoding in H.264.

FIG. 1 is a flowchart indicating a concept of a method of determining afilter strength of an inter-pixel filter at a boundary between an IPCMblock (macroblock) and a non-IPCM block (macroblock) in coding anddecoding schemes according to the H.264 Standard.

FIG. 1 schematically shows the boundary between the two macroblocks oneof which is the non-IPCM macroblock (the left side in the illustration)and the other is the IPCM macroblock (the right side in theillustration). Three circles positioned at the left side in FIG. 1 showthree pixels (typically, denoted as p0, p1, and p2 sequentially from theboundary). These left-side three pixels belong to a first block (pblock) in a first unit (a coded unit block, hereinafter referred to as aCU block). These three pixels also belong to a first macroblock of anon-IPCM type in a macroblock unit block (hereinafter referred to as anMB) that is a unit larger than the first unit.

Likewise, three circles positioned at the right side in FIG. 1 showthree pixels (typically, denoted as q0, q1, and q2 sequentially from theboundary). These three pixels belong to a second block (a q block) inthe first unit. These three pixels also belong to a second macroblock ofan IPCM type in an MB.

Hereinafter, a CU block that belongs to a macroblock of an IPCM type isreferred to as an IPCM block, and a CU block that belongs to amacroblock of a non-IPCM block is referred to as a non-IPCM block. Inother words, a non-IPCM block means a bock that is not an IPCM block.

Hereinafter, a description is given of a method of determining a filterstrength that is applied to pixels q0, q1, p0, and p1 across the blockboundary (or a boundary between block units larger than the unit ofcoding).

A filtering method in H.264 (the filtering method described in Clause8.7 of the Standard) defines that a filter strength for a boundarybetween two blocks is normally determined based on the average value ofa value qPp derived from a quantization parameter QPp of a firstmacroblock and a quantization parameter QPq of a second macroblock. Morespecifically, the following (Expression 1) shown as Expression 8-461 inthe Standard is used.QPav=(QPp+QPq+1)>>1=>(QPp+1)>>1   (Expression 1)

This (Expression 1) shows the following calculation. Filter strengthsare designed such that a stronger (in smoothness) filter is applied asthe value of a quantization parameter is larger, with an aim to, forexample, absorb a quantization error.

In the illustration, a left-side quantization parameter QPp is aquantization parameter that is coded for the first macroblock (p-sideblock). For convenience, QP used here is equivalent in meaning to avalue qP that is used for the purpose of filtering. In addition, aright-side quantization parameter QPq is a quantization parameter thatshould be applied to the second macroblock (q-side block).

Here, as described in Clause 8.7.2 of the H.264 Standard, the value ofthe quantization parameter qPq (QPq in the illustration) of the IPCMblock is set to 0. In other words, “Both sides filtered with weakstrength” is realized. This means that, as for a boundary between twoblocks, a filter having a filter strength is applied to both the blocks.This also means that it is impossible to differentiate filter strengthsfor the respective two blocks. In other words, filtering using the samefilter strength is executed on both the blocks across the boundarybetween an IPCM block and a non-IPCM block.

FIG. 2 is a flowchart illustrating a concept of filtering at a blockboundary described in Clause 8.7 “Deblocking filter process” of theH.264 Standard.

This flowchart roughly explains the following three points regarding anH.264 filter.

(1) Order of Determining Filter Strength (bS) in Clause 8.7.2.1

Step S101 corresponds to the process of “Deviation process for the lumacontent dependent boundary filter strength” described in Clause 8.7.2.1.This process determines a filter strength in filtering on a blockboundary according to a block type and the like. Here, the filterstrength is classified into a level among levels ranging from strongfiltering (bS=4) to no filtering (bS=0). This point is described withreference to FIG. 3.

(2) Process of Setting Quantization Parameter qPz=0 for IPCM Block

Steps S102 to S107 are processes for setting a value of a quantizationparameter qP for determining a filter strength as described withreference to FIG. 1. As for normal non-IPCM blocks (No in Step S102 orS105), the quantization parameter QP [i] (i denotes 0 or 1) of amacroblock to which the non-IPCM block belongs is set as a quantizationparameter qP [i] for determining a filter strength (Step S103 and S106).On the other hand, when a current block is an IPCM block (Yes in S102 orS105), the quantization parameter qP of the IPCM block is set to 0 (StepS104 and S107).

Next, in Step S108, qPav is calculated according to (Expression 1).

(3) One bS (or filterSampleFlag) is Shared by Both Blocks

Hereinafter, a description is given of applying a determined filterstrength (a value) (or a determination flag specifying whether toperform filtering or not) in common to two blocks across a boundary.

First, after Step S108, calculation using Expressions from 8-462 to8-467 in the Standard is performed. More specifically, (1) derivation ofan index for slight adjustment of a filter strength that is set in StepS101 and (2) derivation of a threshold value for edge determination areperformed.

Then, the filter strength determined through these processes is set toboth the blocks (S109). More specifically, even when the filter strengthbS is any one of 1 to 4, the value derived using the common bS derivingmethod is applied to the two blocks. For example, when the filterstrength bS=4 is satisfied, the value of the pixel p of the first blockis derived using Expressions (8-486 and 8-487) in the Standard. Inaddition, the value of the pixel q included in the second block isderived using the same filter strength as the filter strength used inthe derivation of the value of the pixel p. Furthermore, a determinationon whether to perform filtering (derivation of the value offilterSamplesFlag (also referred to as a filtering execution flag)) isperformed in preparation for, for example, a case where a block boundaryis finally found to be an actual edge. More specifically, thisdetermination is made by comparison between two threshold values(two_threths (α, β)) derived in Step S109 and actual pixel values of pand q (see Expression (8-468) in the Standard). However, as describedabove, it is impossible to set different values (or execution ornon-execution) as the filter strengths bS or the filtering executionflags for the respective two blocks.

In other words, in H.264, it is impossible to perform processingsuitable for IPCM when seen within a filtering process.

FIG. 3 is a flowchart indicating the order of deciding (order ofdetermining) a filter strength (bS) that is applied to pixels locatedacross a boundary between two macroblocks, as described in Clause8.7.2.1 of the Standard. This flowchart illustrates the determinationorder in Step S101 shown in FIG. 2, and conforms to the determinationflow in Clause 8.7.2.1 of the Standard.

First, a determination is made as to whether the boundary defined by thepixel p0 in the first block and the pixel q0 in the second block alsocorresponds to a boundary between macroblocks or not (S121). In otherwords, a determination is made as to whether p0 and q0 are locatedacross the macroblock boundary.

When the block boundary between the processing targets is not amacroblock boundary (No in S121), the filter strength (bS) is determinedto be any one of 3, 2, 1, and 0 that is smaller than N (=4) (S124).

On the other hand, when the block boundary between the processingtargets is a macroblock boundary (Yes in S121), a determination is madeas to whether one (or both) of p0 and q0 belongs to a macroblock codedusing the intra prediction mode (S122).

When both the blocks do not belong to a macroblock coded using the intraprediction mode (No in S122), a determination based on anotherdetermination factor is executed (S125).

On the other hand, when at least one of the blocks belongs to amacroblock coded using the intra prediction mode (Yes in S122), thefilter strength is (always) set to bS=4 that means the highest strengthwithout considering any other determination factor (S123).

In this way, the conventional filtering method does not make it possibleto execute internal filtering processes for such two blocks that arelocated across the boundary in different manners (in terms of filterstrengths and application or non-application of a filter). In addition,the Standard considers processes up to the determination of a filterstrength focusing on IPCM, but does not make it possible to performcontrol for outputting raw pixel values of an IPCM block when one of theblocks is an IPCM block and the other is a non-IPCM block.

An IPCM block is a block including pixel values faithfully showing “theoriginal image” without a coding loss.

Accordingly, in the filtering process, it is desirable to controlfiltering at the boundary with an IPCM block or to control applicationof a filter to the IPCM block.

Embodiment 1

Hereinafter, a description is given of a filtering method according toEmbodiment 1 of the present invention.

FIG. 4 illustrates a concept of a method of determining a factor forapplication of the filtering method according to this embodiment anddetermining a filter strength of an inter-pixel filter. Three circles inthe illustration show pixels included in the first block as in FIG. 1.The same elements as in FIG. 1 among the remaining elements are notdescribed again.

A filtering method according to this embodiment is for filtering aplurality of blocks included in an image. Typically, the filteringmethod is applied to deblocking filtering that is performed on aboundary between adjacent blocks. Hereinafter, a description is given ofan example of applying deblocking filtering to the present invention.However, the present invention is also applicable to in-loop filtering(Adaptive Loop Filter) other than deblocking filtering.

The filtering method according to this embodiment is different from thefiltering method described with reference to FIG. 1 in the pointsindicated below.

First, unfiltered pixel values are output as the pixel values of threepixels of the block that is IPCM at the right side in the illustration.

In addition, control is performed to differentiate filtering for thefirst block and filtering for the second block. For example, a filter isapplied to one (at the left side) of the blocks across the boundary inthe illustration, and no filter is applied to the other (at the rightside). In this way, such control for performing the different filteringprocesses between the blocks is performed.

Next, the filter strength for the left-side block to which the filter isapplied is derived based only on the quantization parameter QPp of theleft-side block. In other words, the filter strength of the non-IPCMblock at the left side is derived without using the quantizationparameter QPq of the right-side macroblock or any other substitute fixedvalue (0 in the conventional example).

A determination regarding IPCM in H.264 shown in FIG. 2 is made as towhether or not a current block is an IPCM macroblock. Here, such adetermination as to whether or not a current block is an IPCM macroblockis made based on a prediction unit (PU) that has a variable size. Inother words, an IPCM block below is a block that belongs to a PU blockof an IPCM type, and a non-IPCM block is a block that belongs to a PUblock of a non-IPCM type.

Hereinafter, these operations are described with reference to thedrawings.

FIG. 5 is a flowchart of a processing order in a filtering methodaccording to this embodiment.

The filtering method according to this embodiment is executed as a partof coding processes or decoding processes. Accordingly, this filteringmethod is executed by one of a filtering unit in a coding loop within amoving picture coding apparatus shown in FIG. 6 described later and afiltering unit in a decoding loop within a moving picture decodingapparatus shown in FIG. 9 described later, and a control unit forcontrolling the filter.

The control unit determines whether the PU block type of one of the twoblocks sharing the boundary is IPCM or not (S201). In the exemplary caseof FIG. 4, the right-side PU block is an IPCM block, and thus the one isdetermined to be of an IPCM type. More specifically, the control unitexecutes this determination using a macroblock type, or an attributeparameter of image data such as a motion compensation block size.

When at least one of the two blocks is an IPCM block (Yes in S201), thecontrol unit determines whether the other of the two blocks is an IPCMblock or not (S202). For example, as in the case of the illustration inFIG. 4, the right-side block is an IPCM block. Accordingly, the controlunit determines whether the other block that is the left-side block isan IPCM block or not.

In other words, in steps S201 and S202, the control unit determineswhether each of the blocks is an IPCM block or a non-IPCM block. Morespecifically, the control unit determines (1) whether both of the twoblocks are non-IPCM blocks (No in S201), and (2) whether both of the twoblocks are IPCM blocks (Yes in S202) or (3) whether one of the blocks isan IPCM block and the other is a non-IPCM block (No in S202).

When the other block is an IPCM block (Yes in S202), that is, when boththe blocks are IPCM blocks, filtering is skipped for the pixels p and qof both the blocks (both of the first block and the second block (S203).

On the other hand, when the other block is not an IPCM block (No inS202), that is, only one of the blocks is an IPCM block, and the otheris a non-IPCM block, the control unit performs control for causing thefiltering unit to execute filtering in Steps S204 and S205.

First, the filtering unit executes filtering using a predeterminedstrength on pixels included in the non-IPCM block (for example, thethree pixels at the left side in FIG. 4), and outputs the filtered pixelvalues as the pixel values of the non-IPCM block (S204). In addition,this filtering also uses pixel values of an IPCM block, in addition tothe pixel values of the non-IPCM block. More specifically, the filteringunit smoothes the pixel values of the non-IPCM block and the pixelvalues of the IPCM block to calculate the pixel values of the filterednon-IPCM block.

In addition, the filtering unit outputs the unfiltered pixel values forthe pixels included in the IPCM block (pixels q0, q1, . . . at the qside) (S205). Here, the unfiltered pixel values are output in thefollowing two conceivable cases.

A first method is a method of filtering a non-IPCM block, and outputtingthe original pixel values of an IPCM block without filtering.

A second method is a method of filtering both of a non-IPCM block and anIPCM block, replacing the pixel values of the IPCM block among thefiltered pixel values by the original pixel values before the filtering,and outputting the replacement pixel values. In any one of the cases,the IPCM block's pixel values that are output are the original pixelvalues before the execution of the filtering.

The filtering method can be regarded as involving control for takingdifferent filtering approaches (filter strengths, application ornon-application of a filter, and the number(s) of pixels in theapplication) between the blocks.

The filtering (especially, operations by the control unit and thefiltering unit) in Steps S204 and S205 are described later withreference to FIGS. 6 to 8.

In addition, when both the blocks are non-IPCM blocks in Step S201 (Noin S201), the control unit performs default filtering operation (S206).In other words, the control unit executes filtering using apredetermined filter strength on both the blocks.

Hereinafter, a description is given of a moving picture coding apparatuswhich performs the filtering method.

FIG. 6 is a functional block diagram of a moving picture codingapparatus 100 according to this embodiment of the present invention. Themoving picture coding apparatus 100 shown in FIG. 6 codes an input imagesignal 120 to generate a coded bit stream 132. The moving picture codingapparatus 100 comprises a subtractor 101, an orthogonal transform unit102, a quantization unit 103, an inverse quantization unit 104, aninverse orthogonal transform unit 105, an adder 106, a filtering unit115, a memory 109, a prediction unit 110, a variable length coding unit111, a selecting unit 112, and a control unit 113.

The subtractor 101 calculates a difference between the input imagesignal 120 and a prediction image signal 130 to generate a residualsignal 121. The orthogonal transform unit 102 performs orthogonaltransform on the residual signal 121 to generate a transform coefficient122. The quantization unit 103 quantizes the transform coefficient 122to generate the quantized coefficient 123.

The inverse quantization unit 104 performs inverse quantization on thequantized coefficient 123 to generate the transform coefficient 124. Theinverse orthogonal transform unit 105 performs inverse orthogonaltransform on the transform coefficient 124 to generate a decodedresidual signal 125. The adder 106 adds the decoded residual signal 125and the prediction image signal 130 to generate a decoded image signal126.

The filtering unit 115 filters the decoded image signal 126 to generatean image signal 128, and stores the generated image signal 128 in thememory 109.

The prediction unit 110 selectively performs intra prediction and interprediction using the image signal 128 stored in the memory 109 togenerate a prediction image signal 130.

The variable length coding unit 111 performs variable length coding(entropy coding) on the quantized coefficient 123 to generate a codedsignal 131.

The selecting unit 112 selects the input image signal 120 when a currentblock is an IPCM block, and selects a coded signal 131 when a currentblock is a non-IPCM block. Then, the selecting unit 112 outputs theselected signal as a coded bit stream 132.

The control unit 113 controls the filtering unit 115 and the selectingunit 112.

Here, the orthogonal transform unit 102 and the quantization unit 103are examples of transform and quantization units which generate aquantization coefficient by performing transform and quantization on theresidual signal. In addition, the variable length coding unit 111 is anexample of a coding unit which codes the quantized coefficient togenerate a coded signal. In other words, the inverse quantization unit104 and the inverse orthogonal transform unit 105 are examples of aninverse quantization unit and an inverse transform unit which generate adecoded residual signal by performing inverse quantization and inversetransform on the quantized coefficient.

Here, especially major elements of the moving picture coding apparatus100 according to this embodiment are the control unit 113 and thefiltering unit 115.

As described above, the filtering method according to this embodiment isexecuted as parts of the coding processes and the decoding processes.Accordingly, the filtering unit 115 is located before the memory 109 forholding reference pictures etc. The filtering unit 115 stores, in thememory 109 in the loops, the result of executing the filtering (or theresult of skipping the filtering). In this respect, the filtering unit115 is the same as a filter called a Loop filter in H.264.

In addition, the filtering unit 115 has two input lines. A first one ofthe input signals is a decoded image signal 126 representing the pixelvalues of the non-IPCM block, and a second one of the input signals isan input image signal 120 representing the pixel values of the IPCMblock. Here, the decoded image signal 126 is a reconstructed coded imagesignal after being subjected to transform, quantization, inversequantization, and inverse transform. In addition, the input image signal120 is the original image signal which is not subjected to the codingand decoding.

Under control of the control unit 113, the filtering unit 115 outputsthe unfiltered original pixel values of the IPCM block, and filters thepixel values of the non-IPCM block and outputs the filtered values.

This filtering unit 115 includes a filter unit 107 and a selecting unit108. The filter unit 107 filters the decoded image signal 126 togenerate an image signal 127. The selecting unit 108 selects the imagesignal 127 when a current block is an IPCM block, and selects an inputimage signal 120 when a current block is a non-IPCM block and thenoutputs the selected signal as an image signal 128.

Each of FIGS. 7A and 7B is an illustration of an example of pixelsacross a boundary between two blocks. In the example shown in FIG. 7A,the two blocks are adjacent to each other in the horizontal direction.Here, the block including the pixels p0 to pn at the left side isreferred to as a first block. This first block is a non-IPCM block. Inaddition, the other block is referred to as a second block. This secondblock is an IPCM block. Here, as shown in FIG. 7B, the filtering in thisembodiment is naturally applicable in the case where an IPCM block and anon-IPCM block are adjacent to each other in the vertical direction.

Hereinafter, a description is given of a specific example of operationsby the filtering unit 115.

Each of FIG. 8A and FIG. 8B is an illustration of operations performedby the filtering unit 115 in the case of filtering pixels p [i] and q[j] included in the two blocks illustrated in FIG. 7A. In other words,the first block belongs to the non-IPCM block, and the second block isthe IPCM block.

The filtering unit 115 performs operations shown in FIG. 8A and FIG. 8Baccording to a control signal from the control unit 113.

FIG. 8A is an illustration of an operation by the filtering unit 115 onthe non-IPCM block. This operation corresponds to Step S204 shown inFIG. 5. In other words, the filtering unit 115 calculates output resultspf0, pf1, . . . of the pixels corresponding to the first block, usingboth the pixel values (p0, p1, . . . ) of the first block and the pixelvalues (q0, q1, . . . ) of the second block.

FIG. 8B is an illustration of operations by the filtering unit 115 onthe IPCM block. This operation corresponds to Step S205 shown in FIG. 5.In other words, the filtering unit 115 outputs the same values(unfiltered pixel values) as the input values q0, q1, and q2, for thepixels of the second block.

Hereinafter, a description is given of a moving picture decodingapparatus which performs the filtering method.

FIG. 9 is a functional block diagram of a moving picture decodingapparatus according to this embodiment.

The moving picture decoding apparatus 200 shown in FIG. 9 decodes thecoded bit stream 232 to generate an output image signal 220. Here, thecoded bit stream 232 is, for example, a coded bit stream 132 generatedby the moving picture coding apparatus 100.

This moving picture decoding apparatus 200 comprises an inversequantization unit 204, an inverse orthogonal transform unit 205, anadder 206, a filtering unit 215, a memory 209, a prediction unit 210, avariable length decoding unit 211, a distributing unit 212, and acontrol unit 231.

The distributing unit 212 supplies the coded bit stream 232 to thefiltering unit 215 when a current block is an IPCM block, and suppliesthe coded bit stream 232 to the variable length decoding unit 211 when acurrent block is a non-IPCM block.

The variable length decoding unit 211 performs variable length decoding(entropy decoding) on the coded bit stream 232 to generate a quantizedcoefficient 223.

The inverse quantization unit 204 performs inverse quantization on thetransform coefficient 223 to generate the transform coefficient 224. Theinverse orthogonal transform unit 205 performs inverse orthogonaltransform on the transform coefficient 224 to generate a decodedresidual signal 225. The adder 206 adds the decoded residual signal 225and the prediction image signal 230 to generate a decoded image signal226.

The filtering unit 215 filters the decoded image signal 226 to generatean image signal 228, and stores the generated image signal 228 in thememory 209.

This filtering unit 215 includes a filter unit 207 and a selecting unit208. The filter unit 207 filters the decoded image signal 226 togenerate an image signal 227. The selecting unit 208 selects the imagesignal 227 when a current block is an IPCM block, and selects an inputimage signal 232 when a current block is a non-IPCM block and thenoutputs the selected signal as an image signal 228.

In addition, the image signal 228 stored in the memory 209 is output asan output image signal 220.

The prediction unit 210 selectively performs intra prediction and interprediction using the image signal 228 stored in the memory 209 togenerate a prediction image signal 230.

The control unit 213 controls the filtering unit 215 and thedistributing unit 212.

Here, the variable length decoding unit 211 is an example of a decodingunit which decodes the coded bit stream to generate a quantizedcoefficient. In other words, the inverse quantization unit 204 and theinverse orthogonal transform unit 205 are examples of an inversequantization unit and an inverse transform unit which generate a decodedresidual signal by performing inverse quantization and inverse transformon the quantized coefficient.

Here, operations by the filtering unit 215 are the same as operations bythe filtering unit 115 of the moving picture coding apparatus 100. Thecontrol unit 213 is different from the control unit 113 included in themoving picture coding apparatus 100 in the point of determining whetherthe PU unit type of the first block or the second block is IPCM or notfrom the coded bit stream 232 that is an input coded string, but is thesame in the other functions.

Hereinafter, descriptions are given of structures of variations of thefiltering units 115 and 215.

Each of FIG. 10A to FIG. 10H is an illustration of a conceivableimplementation regarding a filter input-output relationship of filteringunits 115 and 215.

As shown in FIG. 10A, each of the filter units 107 and 207 may includefilter units 301 and 302 connected in series. For example, the firstfilter unit 301 and the second filter unit 302 may perform differentprocesses. In this case, for example, the whole filtering processes arebypassed for the IPCM block.

As shown in FIG. 10B, the filter unit 311 may perform filtering usingboth the input signals. In this case, the selecting unit 312 outputsunfiltered values for the IPCM block, and the filter unit 311 outputsfiltered values for the non-IPCM block.

As shown in FIG. 10C, it is also good to perform filtering processesdifferent between the IPCM block and the non-IPCM block. For example,different filtering processes may be filtering processes using differentfilter strengths. In addition, for example, the filter strength for theIPCM block may be lower than the filter strength for the non-IPCM block.

More specifically, the distributing unit 321 outputs the input signal tothe filter unit 322 when a current block is a non-IPCM block, andoutputs the input signal to the filter unit 323 when a current block isan IPCM block. Here, the input signals include both the decoded imagesignal 126 and the input image signal 120. The filter unit 322 performsfiltering of a first filter strength using the input signal to generatepixel values of the current block. The filter unit 322 performsfiltering using a second filter strength lower than the first filterstrength to generate pixel values of the current block. The selectingunit 324 outputs the pixel values of the current block filtered by thefilter unit 322 when the current block is the non-IPCM block, andoutputs the pixel values of the current block filtered by the filterunit 323 when the current block is the IPCM block.

As shown in FIG. 10D, processing on the IPCM block does not always needto be performed. More specifically, the distributing unit 331 outputsthe input signal to the filter unit 332 when a current block is anon-IPCM block, and outputs the input signal to the selecting unit 333when a current block is an IPCM block. The selecting unit 333 outputsthe pixel values of the current block filtered by the filter unit 332when the current block is the non-IPCM block, and outputs the pixelvalues of the current block in the signal from the filter unit 331 whenthe current block is the IPCM block.

As shown in FIG. 10E, it is possible to switch input sides of filterunits instead of switching output sides of the filter units.Furthermore, the numbers of the stages of filter units are differentbetween an IPCM block and a non-IPCM block. More specifically, thedistributing unit 341 outputs the input signal to the filter unit 342when a current block is a non-IPCM block, and outputs the input signalto the filter unit 344 when a current block is an IPCM block. The filterunit 342 performs filtering using the input signal. The filter unit 343performs filtering using the signal filtered by the filter unit 342, andoutputs the pixel values of the current filtered block. The filter unit344 performs filtering using the input signal, and outputs the pixelvalues of the current filtered block. Here, the filtering performed bythe filter unit 344 may be the same as or different from the filteringperformed by the filter unit 342 and the filtering performed by thefilter unit 343.

As shown in FIG. 10F, it is possible to switch output sides of filterunits. More specifically, the filter unit 351 performs filtering usingthe first input signal. The filter unit 352 performs filtering using thesignal filtered by the filter unit 351, and outputs the pixel values ofthe current filtered block. The filter unit 353 performs filtering usingthe second input signal, and outputs the pixel values of the currentfiltered block. The selecting unit 354 outputs the pixel values of thecurrent block filtered by the filter unit 352 when the current block isthe non-IPCM block, and outputs the pixel values of the current blockfiltered by the filter unit 353 when the current block is the IPCMblock.

Here, outputting an unfiltered value involves replacing a pixel valueresulting from filtering by the original input value p and outputtingthe replacement value.

As shown in FIG. 10G, it is possible to use a signal filtered in one oftwo lines in filtering that is performed in the other line. Morespecifically, the filter unit 361 performs filtering using the secondinput signal. The filter unit 362 performs filtering using the firstinput signal and a signal filtered by the filter unit 361. The selectingunit 363 outputs the pixel values of the current block filtered by thefilter unit 362 when the current block is the non-IPCM block, andoutputs the pixel values of the current block filtered by the filterunit 361 when the current block is the IPCM block. The selecting unit363 may output the pixel values of the current block filtered by thefilter unit 362 when the current block is the IPCM block, and output thepixel values of the current block filtered by the filter unit 361 whenthe current block is the non-IPCM block.

As shown in FIG. 10H, a value stored once in the memory 373 may be usedas an input. More specifically, the selecting unit 371 selects one ofthe input signal and the signal stored in the memory 373. The filterunit 372 performs filtering using the signal selected by the selectingunit 371.

These are examples, and thus it is only necessary for the filtering unit115 according to this embodiment to exert a function of finally“outputting unfiltered values for the pixels in an IPCM block”.

Hereinafter, a description is given of a modified version of a filteringmethod according to the present invention. FIG. 11 is a flowchart ofoperations in the modified version of the filtering method according tothis embodiment.

It has been described that filtering is applied to the non-IPCM block inStep S204 of FIG. 5 and unfiltered pixel values of the IPCM block areoutput in Step S205 of FIG. 5. However, these processes may be realizedin the steps indicated below. For example, it is possible to performprocesses shown in FIG. 11 instead of Steps S204 and S205 shown in FIG.5.

First, pixel values of a first block (block [0]) and a second block(block y [1]) adjacent to each other are obtained (S221). Here, forexample, the first block is a non-IPCM block, and the second block is anIPCM block.

Next, a filter strength bS [0] that is applied to the first block and afilter strength bS [1] that is applied to the second block are derived(S222 and S223). Here, the filter strength bS [0] and the filterstrength bS [1] show different strengths. In the conventional art, onlyone filter strength is set for a block boundary. For example, in thisembodiment, the filter strength for the IPCM block is set lower than thefilter strength for the non-IPCM block.

Next, both the blocks are filtered using the filter strength bS [0], andthe pixel values of the first block after the filtering are output(S224). Next, both the blocks are filtered using the filter strength bS[1], and the pixel values of the second block after the filtering areoutput (S225).

Here, it is possible to control application or non-application offiltering by setting the value of the filter strength to 0. In otherwords, it is also good to derive for each of the blocks a flag(filterSamplesFlag) for controlling application or non-application offiltering.

As described above, the filtering method according to this embodimentmakes it possible to execute filtering on one of the blocks using thefirst filter strength and execute filtering on the other block using thesecond filter strength. In addition, the filtering method makes itpossible to perform such processing in filtering processes.

FIG. 12 is a flowchart of operations in a variation of the filteringmethod according to this embodiment. The processes shown in FIG. 12further include Step S401, in addition to the processes shown in FIG. 3

This Step S401 is added to provide an appropriate filter strength to anIPCM block which is inevitably determined to be a block that is intrapredicted. In Step S401, a determination is made as to whether at leastone of the first block and the second block is an IPCM block or not.When at least one of the first block and the second block is the IPCMblock (Yes in S401), a filter strength (bS) is determined to be any oneof 3, 2, 1, and 0 that is smaller than N (=4) (S124). In addition, whenboth the first block and the second block are non-IPCM blocks (No inS401), the filter strength is set to bS=N which means the higheststrength (S123).

In the case of the filtering method shown in FIG. 3, when one or both ofthe blocks is a macroblock coded using the intra prediction mode (Yes inS122), the filter strength itself is always set to be bS=4 which meansthe highest strength without considering any other determination factor.

On the other hand, in the case of this embodiment's variation shown inFIG. 12, when one or both of the blocks is a macroblock coded using theintra prediction mode (Yes in S122) and when one of the blocks is anIPCM block (Yes in S401), a filter strength (bS=0 to 3) lower than thefilter strength (bS=4) set in Step S123 is set.

FIG. 13 is an illustration of filter strengths determined using thefiltering method according to this embodiment and block units whichdefine a boundary.

As shown in FIG. 13, when a macroblock MB [0] is a macroblock codedusing the inter prediction mode and a macroblock MB [1] is a macroblockcoded using the intra prediction mode (Yes in S122) and when both thefirst and second blocks are non-IPCM blocks (No in S401), bS=4 is set toboth the blocks (S123).

On the other hand, when a PU block [0] is coded using a non-IPCM modeand a PU block [1] is coded using an IPCM mode, that is, when a Cu block[0] is a non-IPCM block and a Cu block [1] is an IPCM block (Yes inS401), bS=any one of 0 to 3 is set to each of the Cu block [0] and CUblock [1]. In this example, bS=0 is set to the Cu block [1] that is anIPCM block, and bS=any one of 1 to 3 is set to the Cu block [0] that isa non-IPCM block.

Each of FIG. 14A and FIG. 14B is an illustration of a state in which anapplication range of a flag indicating that a filter is ON is extendedby handling an IPCM block according to this embodiment. FIG. 14A shows,as a comparison example, a case of not applying an approach in thisembodiment. FIG. 14B shows a case of applying the approach in thisembodiment.

As shown in FIG. 14B, it is possible to extend the application range ofthe flag indicating that a filter is ON by using the filtering methodaccording to this embodiment.

As described above, the filtering method according to this embodimentemploys, for the determination, an implicit code interpretation rulethat the filtering unit or the control unit “does not filter an IPCMblock” in the in-loop filtering. In this way, as shown in FIG. 14A andFIG. 14B, it is possible to specify whether a filter is enabled ordisabled for a coded string in a larger range. In this way, thefiltering method according to this embodiment reduces the amount ofbits.

The filtering methods, moving picture coding apparatuses, and movingpicture decoding apparatuses according to the embodiments of the presentinvention have been described above, but the present invention is notlimited to these embodiments.

For example, it is also possible to combine at least parts of functionsof the filtering methods, moving picture coding apparatuses, movingpicture decoding apparatuses according to the embodiments and thevariations thereof.

In addition, the division of functional blocks in each of the blockdiagrams is exemplary. It is also possible to implement some of thefunctional blocks as a functional block, divide a functional block intoplural blocks, and/or move part of the function(s) to any of thefunctional blocks. In addition, the functions of the plural functionalblocks having functions similar to each other may be exerted in parallelor in time division by hardware or software.

In addition, the execution order of the plural steps of each of thefiltering methods is provided as an example for specifically explainingthe present invention, and thus other orders are also possible. Inaddition, part of the steps may be executed simultaneously with (inparallel to) any of the other steps.

For example, the order of Steps S201 and S202 shown in FIG. 5 is notlimited to the described order. In other words, it is only necessarythat Steps S204 and S205 are executed as a result when “one of twoblocks across a boundary is included in an IPCM block, and the other isnot included in an IPCM block”. In addition, the order of Steps S204 andS205 may also be arbitrary.

Likewise, the order of Steps S222 to S225 shown in FIG. 11 is notlimited to the described order. More specifically, the order of StepsS222 to S225 may be arbitrary as long as Step S224 is after Step S222and Step S225 is after S223.

Embodiment 2

The processing described in each of embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method (image decoding method) described in each ofembodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) described in each of embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image coding apparatus using theimage coding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 15 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 15, and a combination inwhich any of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital video camera, iscapable of capturing both still images and video. Furthermore, thecellular phone ex114 may be the one that meets any of the standards suchas Global System for Mobile Communications (GSM) (registered trademark),Code Division Multiple Access (CDMA), Wideband-Code Division MultipleAccess (W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of embodiments (i.e., the camerafunctions as the image coding apparatus in the present invention), andthe coded content is transmitted to the streaming server ex103. On theother hand, the streaming server ex103 carries out stream distributionof the transmitted content data to the clients upon their requests. Theclients include the computer ex111, the PDA ex112, the camera ex113, thecellular phone ex114, and the game machine ex115 that are capable ofdecoding the above-mentioned coded data. Each of the devices that havereceived the distributed data decodes and reproduces the coded data(i.e., functions as the image decoding apparatus in the presentinvention).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the image data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 16. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of embodiments (i.e.,data coded by the image coding apparatus in the present invention). Uponreceipt of the multiplexed data, the broadcast satellite ex202 transmitsradio waves for broadcasting. Then, a home-use antenna ex204 with asatellite broadcast reception function receives the radio waves. Next, adevice such as a television (receiver) ex300 and a set top box (STB)ex217 decodes the received multiplexed data, and reproduces the decodeddata (i.e., functions as the image coding apparatus in the presentinvention).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording media ex215, such as a DVD anda BD, or (i) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision ex300.

FIG. 17 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (which function as the imagecoding apparatus and the image decoding apparatus); and an output unitex309 including a speaker ex307 that provides the decoded audio signal,and a display unit ex308 that displays the decoded video signal, such asa display. Furthermore, the television ex300 includes an interface unitex317 including an operation input unit ex312 that receives an input ofa user operation. Furthermore, the television ex300 includes a controlunit ex310 that controls overall each constituent element of thetelevision ex300, and a power supply circuit unit ex311 that suppliespower to each of the elements. Other than the operation input unitex312, the interface unit ex317 may include: a bridge ex313 that isconnected to an external device, such as the reader/recorder ex218; aslot unit ex314 for enabling attachment of the recording medium ex216,such as an SD card; a driver ex315 to be connected to an externalrecording medium, such as a hard disk; and a modem ex316 to be connectedto a telephone network. Here, the recording medium ex216 canelectrically record information using a non-volatile/volatilesemiconductor memory element for storage. The constituent elements ofthe television ex300 are connected to each other through a synchronousbus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underflow may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 18 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 19 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex233 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 17. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 20A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 20B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of embodiments (i.e.,functions as the image coding apparatus in the present invention), andtransmits the coded video data to the multiplexing/demultiplexing unitex353. In contrast, during when the camera unit ex365 captures video,still images, and others, the audio signal processing unit ex354 codesaudio signals collected by the audio input unit ex356, and transmits thecoded audio data to the multiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of embodiments (i.e., functions as the imagedecoding apparatus in the present invention), and then the display unitex358 displays, for instance, the video and still images included in thevideo file linked to the Web page via the LCD control unit ex359.Furthermore, the audio signal processing unit ex354 decodes the audiosignal, and the audio output unit ex357 provides the audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of embodiments can be used in any to of thedevices and systems described. Thus, the advantages described in each ofembodiments can be obtained.

Furthermore, the present invention is not limited to embodiments, andvarious modifications and revisions are possible without departing fromthe scope of the present invention.

Embodiment 3

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG-4 AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconform cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 21 illustrates a structure of the multiplexed data. As illustratedin FIG. 21, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary video to be mixed with the primary audio.

FIG. 22 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 23 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 23 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 23, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 24 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 24. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 25 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 26. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 26, the multiplexed data includes a system rate,a reproduction start time, and a reproduction end time. The system rateindicates the maximum transfer rate at which a system target decoder tobe described later transfers the multiplexed data to a PID filter. Theintervals of the ATSs included in the multiplexed data are set to nothigher than a system rate. The reproduction start time indicates a PTSin a video frame at the head of the multiplexed data. An interval of oneframe is added to a PTS in a video frame at the end of the multiplexeddata, and the PTS is set to the reproduction end time.

As shown in FIG. 27, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 28 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute information isobtained from the multiplexed data. Next, in Step exS101, it isdetermined whether or not the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of embodiments. When it is determined that the stream type or thevideo stream attribute information indicates that the multiplexed datais generated by the moving picture coding method or the moving picturecoding apparatus in each of embodiments, in Step exS102, decoding isperformed by the moving picture decoding method in each of embodiments.Furthermore, when the stream type or the video stream attributeinformation indicates conformance to the conventional standards, such asMPEG-2, MPEG-4 AVC, and VC-1, in Step exS103, decoding is performed by amoving picture decoding method in conformity with the conventionalstandards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard, an appropriatedecoding method or apparatus can be selected. Thus, it becomes possibleto decode information without any error. Furthermore, the moving picturecoding method or apparatus, or the moving picture decoding method orapparatus in the present embodiment can be used in the devices andsystems described above.

Embodiment 4

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 29 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit ex505 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recording mediaex215. When data sets are multiplexed, the data should be temporarilystored in the buffer ex508 so that the data sets are synchronized witheach other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present inventionis applied to biotechnology.

Embodiment 5

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, theprocessing amount probably increases. Thus, the LSI ex500 needs to beset to a driving frequency higher than that of the CPU ex502 to be usedwhen video data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 30illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 29.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 29. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment 3 is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment 3 but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 32. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 31 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofEmbodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG-4 AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG-4 AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 6

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a mobile phone. In order to enable decoding the pluralityof video data that conforms to the different standards, the signalprocessing unit ex507 of the LSI ex500 needs to conform to the differentstandards. However, the problems of increase in the scale of the circuitof the LSI ex500 and increase in the cost arise with the individual useof the signal processing units ex507 that conform to the respectivestandards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex900 in FIG. 33A showsan example of the configuration. For example, the moving picturedecoding method described in each of embodiments and the moving picturedecoding method that conforms to MPEG-4 AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG-4 AVC. In contrast, a dedicateddecoding processing unit ex901 is probably used for other processingunique to the present invention. Since the present invention ischaracterized by intra prediction processing in particular, for example,the dedicated decoding processing unit ex901 is used for intraprediction processing. Otherwise, the decoding processing unit isprobably shared for one of the entropy coding, inverse quantization,deblocking filtering, and motion compensation, or all of the processing.The decoding processing unit for implementing the moving picturedecoding method described in each of embodiments may be shared for theprocessing to be shared, and a dedicated decoding processing unit may beused for processing unique to that of MPEG-4 AVC.

Furthermore, ex1000 in FIG. 33B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to the present invention, a dedicated decoding processing unitex1002 that supports the processing unique to another conventionalstandard, and a decoding processing unit ex1003 that supports processingto be shared between the moving picture decoding method in the presentinvention and the conventional moving picture decoding method. Here, thededicated decoding processing units ex1001 and ex1002 are notnecessarily specialized for the processing of the present invention andthe processing of the conventional standard, respectively, and may bethe ones capable of implementing general processing. Furthermore, theconfiguration of the present embodiment can be implemented by the LSIex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding method inthe present invention and the moving picture decoding method inconformity with the conventional standard.

Although only some exemplary embodiments of the present invention havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the present invention. Accordingly, all such modificationsare intended to be included within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to filtering methods, moving picturecoding apparatuses, and moving picture decoding apparatuses. Forexample, the present invention is applicable to high-definition imagedisplay apparatuses and image capturing apparatuses such as televisionreceivers, digital video recorders, car navigation systems, digitalcameras, and digital video cameras.

The invention claimed is:
 1. An encoding method for encoding an image,said encoding method comprising: filtering a first block and a secondblock which are adjacent to each other in the image to generate filtereddata, using values of pixels respectively included in the first blockand the second block, each of the first block and the second block beingeither an Intra Pulse Code Modulation (IPCM) block or a non-IPCM block;and determining (i) whether both of the first block and the second blockare non-IPCM blocks; (ii) whether both of the first block and the secondblock are IPCM blocks; or (iii) whether one of the first block and thesecond block is an IPCM block and the other of the first block and thesecond block is a non-IPCM block, wherein, when it is determined in saiddetermining that the first block is a non-IPCM block and the secondblock is an IPCM block, the encoding method further comprises:generating a reconstructed image including (i) a part of the filtereddata generated in said filtering as the pixels in the first block, and(ii) unfiltered pixels in the second block, instead of a part of thefiltered data generated in said filtering, as the pixels in the secondblock; performing prediction for the first block using the reconstructedimage to generate a prediction image block; transforming and quantizinga difference image block that represents a difference between the firstblock and the prediction image block; and generating an encodedbit-stream including the second block itself and the transformed andquantized difference image block, wherein in the filtering, a fixedvalue is not used as a quantization parameter of an IPCM block, and thefiltering is performed using the quantization parameter of the IPCMblock.
 2. An encoding apparatus for encoding an image, comprising:control circuitry, and storage accessible from the control circuitry,wherein the control circuitry is configured to perform, using thestorage, the encoding method according to claim
 1. 3. The encodingmethod according to claim 1, wherein, in said filtering, the filtereddata is generated by performing filtering using both the values of thepixels in the IPCM block and the values of the pixels in the non-IPCMblock.
 4. The encoding method according to claim 1, wherein saidfiltering is deblocking filtering performed on a boundary between thefirst block and the second block.
 5. The encoding method according toclaim 1, further comprising setting a first filter strength for thenon-IPCM block, and setting a second filter strength for the IPCM block,the second filter strength being lower than the first filter strength,wherein in said filtering, the non-IPCM block is filtered using thefirst filter strength, and the IPCM block is filtered using the secondfilter strength.
 6. The encoding method according to claim 5, whereinthe second filter strength specifies that filtering is skipped.
 7. Theencoding method according to claim 5, further comprising: determiningwhether or not the non-IPCM block is a block to be intra coded; andsetting the first filter strength for a non-IPCM block determined not tobe intra coded, the first filter strength being lower than a filterstrength for a non-IPCM block to be intra coded.
 8. An encodingapparatus for encoding an image, said encoding apparatus comprising: afiltering unit configured to filter a first block and a second blockwhich are adjacent to each other in an image to generate filtered data,using values of pixels respectively included in the first block and thesecond block, each of the first block and the second block being eitheran Intra Pulse Code Modulation (IPCM) block or a non-IPCM block; adetermining unit configured to determine (i) whether both of the firstblock and the second block are non-IPCM blocks; (ii) whether both of thefirst block and the second block are IPCM blocks; or (iii) whether oneof the first block and the second block is an IPCM block and the otherof the first block and the second block is a non-IPCM block; areconstructing unit configured to generate, when it is determined bysaid determining unit that the first block is a non-IPCM block and thesecond block is an IPCM block, a reconstructed image including (i) apart of the filtered data generated by said filtering unit as the pixelsin the first block, and (ii) unfiltered pixels in the second block,instead of a part of the filtered data generated by said filtering unit,as the pixels in the second block; a prediction unit configured toperform prediction for the first block using the reconstructed image togenerate a prediction image block; a transform and quantization unitconfigured to transform and quantize a difference image block thatrepresents a difference between the first block and the prediction imageblock; and an encoding unit configured to generate an encoded bit-streamincluding the second block itself and the transformed and quantizeddifference image block, wherein in the filtering of the first block andthe second block, a fixed value is not used as a quantization parameterof an IPCM block, and the filtering of the first block and the secondblock is performed using the quantization parameter of the IPCM block.